Single cell gene expression data of CD45 high to intermediate immune cells from T cell replete and deficient mice harboring EO771 breast cancer metastases.

Resident and infiltrating myeloid cells are frequently reported to be tumor-promoting upon incidence of BCBM, but these cells are often poorly discriminated. We utilized scRNAseq to transcriptionally discriminate key immune cell populations and identify that microglia are predominantly pro-inflammatory upon BCBM initiation, and driven to an antigen presenting phenotype by infiltrating T cells. Myelinated cells were removed from whole brain homogenates of C57BL/6 and RAG1-KO mice by density gradient and sorted for CD45hi-int cells by FACS.